China has been rocked by a string of school attacks in the past two months, in which dozens have been killed or wounded.

China's Premier Wen Jiabao has said the attacks show the country has "social tensions" which must be addressed.

The education ministry has ordered all schools to upgrade their security facilities, teach students about safety and ensure that young children were escorted home.

Some local police authorities have distributed steel pitchforks and pepper spray to security guards in schools but such measures are considered expensive and their effectiveness is unproven.

But Mr Wen told a Hong Kong television channel on Thursday that as well as boosting the security presence, China needed to "handle social problems, resolve disputes and strengthen mediation at the grassroots level".

Discourage copycats?

On Wednesday, seven children thought to be under the age of six and two adults were hacked to death at a kindergarten near Hanzhong city in Shaanxi province. The attacker later killed himself, Xinhua reported.

In March, a man stabbed to death eight pupils at a school in Fujian province. He was executed soon afterwards.